1. Technical Field
The present application is directed to battery cells and systems and, more particularly, to lithium ion battery cells and systems that may be used in a vehicle, such as an electric and/or hybrid vehicle, having an electric drive motor.
2. Related Art
Re-chargeable batteries, such as lithium ion polymer batteries, have a wide range of applications. These include, for example, laptop batteries, cell phone batteries, as well as power for other personal electronic devices. Such devices require low weight batteries having a moderate power output. However, lithium ion polymer batteries are also capable of providing power to devices needing substantially more power output than the personal electronic devices noted above. For example, high output lithium ion polymer batteries may be used to power industrial equipment, high power communications facilities, mobile vehicles, etc. The use of high output lithium ion polymer battery systems may be particularly significant in the area of mobile vehicle propulsion.
The public has become increasingly sensitive to cost and environmental issues associated with the use of fossil-based fuels. One concern is the emissions from vehicles burning fossil-based fuels and the corresponding pollution.
Alternatives to such vehicles include electric vehicles that are solely driven by electric motors, and hybrid electric vehicles that employ both electric motors and fossil-based fuel engines. These alternatives are likely to play an increasingly important role as substitutes for current vehicles.
Although consumers are attracted to the environmental benefits of pure electric and hybrid vehicles, they want vehicles which use electric motors to have the same general characteristics as their fossil-fuel counterparts. Battery performance and safety issues must be overcome to achieve these goals. To this end, lithium ion batteries are preferable to other more conventional battery types. Lithium ion batteries are useful for this purpose in that they have a high energy density which reduces the amount of space needed for the battery in the vehicle. Further, they may be constructed so that they weigh less than the more conventional battery types.
Battery systems for use with electric motors employed in pure electric and hybrid vehicles are currently deficient in many respects. Individual battery cells of the battery system are frequently heavy, bulky, and unreliable. Further, current battery cells are neither constructed nor used to effectively provide the high power output needed to accelerate the vehicle at an acceptable acceleration level. Still further, individual battery cells use electrochemistry, cell core constructions, electrical interconnections, and shell constructions that are often unreliable, unsafe, and generally not suitable for use in electrical powered vehicles.
To overcome the power deficiencies associated with individual battery cells, attempts have been made to interconnect multiple individual battery cells with one another so that their combined power output provides the necessary driving power. The interconnections between the individual battery cells, again, are often unreliable. Further, little has been accomplished to ensure the safety of such multi-cell battery systems. Short-circuits as well as explosions have not been adequately addressed. High power output battery systems must be constructed to address issues such as performance, longevity, reliability, and safety if they are to find a place in the large number of applications available to such systems.